[Motor Evoked Potential].

Motor evoked potential(MEP)is the most widely used intraoperative neurophysiological monitoring measure. It includes cortical direct stimulation MEP(dMEP), which directly stimulates the primary motor cortex of the frontal lobe identified by short-latency somatosensory evoked potentials, and transcranial MEP(tcMEP), which involves high-current or high-voltage transcranial stimulation using cork-screw electrodes installed in the scalp. dMEP is performed in brain tumor surgery close to the motor area. tcMEP is simple, safe, and widely used in spinal and cerebral aneurysm surgeries. The increase in sensitivity and specificity with compound muscle action potential(CMAP)after peripheral nerve stimulation normalization performed in MEP to remove the effect of muscle relaxants is unclear. However, tcMEP for decompression in compressive spinal and spinal nerve diseases may predict the recovery of postoperative neurological symptoms with CMAP normalization. The anesthetic fade phenomenon can be avoided with CMAP normalization. The cutoff rate of loss of amplitude that causes postoperative motor paralysis in intraoperative MEP monitoring is 70%-80%, and setting an alarm at each facility based on this is necessary.